Host-Based X.25 Configuration Concepts

DTS Configuration Branch

NMMGR takes you down specific configuration "branches" to allow you to enter configuration values required by various subsystems or products. The DTS branch allows you to configure the Datacommunications And Terminal Subsystem (DTS), which defines the physical connections and configuration parameters for the computer, its DTCs, and all DTC-connected devices.

If you are configuring only PAD support, you need only traverse the DTS branch of NMMGR. You will use this branch to configure both locally connected devices and PAD connected devices. To access this branch of NMMGR, from the Main screen, answer "N" (no) to the question "Are you using OpenView DTC Manager?" and "Y" (yes) to the question "Do you have X.25 system-to-system or PAD connections?". Press the [Save Data] key, then press the [DTS] function key.

Using the DTS configuration branch, you configure link information for the DTCs connected to the system. For each DTC, you specify the card types the DTC contains, along with logging class and PAD access information if one of the cards is a DTC/X.25 Network Access card. For each individual card, you configure device connection parameters pertinent to the card's type.

For each DTC/X.25 Network Access card you configure, you also specify X.25 level 1, level 2, and level 3 parameters according to your X.25 network subscription. You may also elect to configure security for PAD access.

Complete step-by-step procedures for configuring the DTS branch are provided in Chapter 3 “Configuring DTCs Step-by-Step” of this manual.

NS Configuration Branch

Connections for system-to-system require that you traverse an NS configuration branch to configure X.25 iX System Access. You reach this branch by pressing the [NS] function key at the Main NMMGR screen.

Step-by-step procedures for X.25 iX System Access configuration are in Chapter 6 “Configuring X.25 Links Step-by-Step” of this manual.

	NOTE: The X.25 iX System Access procedure described in this manual assumes the use of guided configuration. While it is possible to configure this link using non-guided configuration, Hewlett-Packard strongly recommends the use of the guided configuration process.

Nailed and Non-Nailed Connections

A nailed device is one that is permanently associated with an ldev number through the NMMGR configuration of an MPE/iX system. Any time a connection exists between a system and one of its nailed devices the same ldev number will belong to that device. This ldev number is reserved for the use of that connection and only that connection. While devices attached through a private or public PAD may be either nailed or non-nailed, all serial devices attached either locally or through a modem must be configured with nailed connections on host-based systems.

Since only nailed devices can be accessed programmatically, all printers must also be nailed, as must any other serial devices that will be accessed programmatically at any time.

A non-nailed device is a device that is able to establish a connection to an MPE/iX host system but has no permanently assigned ldev number in the NMMGR configuration file of that system. Instead, ldev numbers are dynamically associated with a device connection at the time the user requests the connection. The user of a non-nailed device is able to establish a session provided two conditions are met: a connection must be available on the host and the non-nailed device profile specified in the host configuration must match the characteristics of the device requesting the connection.

When the user at a PAD-connected device with a non-nailed connection logs on to the system, an ldev number is assigned from a pool of available ldev numbers defined through the host system's NMMGR configuration. When the connection is ended (the user logs off) the assigned ldev number is returned to the pool of ldev numbers and becomes available for use by a different device connection.

Non-nailed device connections provide several major advantages. They simplify the configuration that must be done on each MPE/iX system, since configuration values do not have to be entered separately for each PAD device that will be able to access that system. Non-nailed connections also make it possible for you to add serial devices to the network without having to reconfigure each host so that it will recognize the additional devices. Finally, configuring a pool of non-nailed devices makes it possible for the number of users with potential access to a system to exceed the session limit of the system. The pool of non-nailed ports that you configure cannot exceed the session limit, and the number of users logged on at a given time must still be within the session limit.

When the user connects to the system through a public PAD, the connection will use a non-nailed device on the host.